The present disclosure relates to an image pickup apparatus and a camera module in which an optical sensor such as a CCD (charge coupled device) and a CMOS (complementary metal oxide semiconductor) image sensor (CIS) is configured as a chip scale package.
As a simple package method for an optical sensor, a wafer chip scale package (WCSP) structure has been proposed.
FIG. 1 is a view showing a basic structure of a WCSP structure.
In a WCSP structure 1, disposed is a sealing glass (cover glass) 3 as a sealing material for protecting an upper portion of an optical element area 21 serving as a light receiving unit of a front surface of an optical device 2 serving as an optical sensor (sensor chip).
In the WCSP structure 1, the sealing glass 3 is disposed on a peripheral portion excluding the optical element area (light receiving unit) 21 of the optical device 2 with a resin 4 intervened. Therefore, in the WCSP structure 1, between the light receiving unit 21 of the optical device 2 and an opposed surface 31 of the sealing glass 3 with respect to the optical element area (light receiving unit) 21, a cavity 5 is formed.
In the CSP structure, an electrode 6 is formed with a through silicon via (TSV) that penetrates the sensor chip from the front surface to the back surface thereof, thereby eliminating wirings using wire bond, which makes it possible to bond the glass in a clean room in a wafer state.
As a result, it is possible to attain a size reduction, a cost reduction, and a dustless condition as compared to a COB (Chip On Board) type package of a past technique.
FIG. 2 is a view showing another structure of a WCSP structure.
A WCSP structure 1A shown in FIG. 2 is configured as a WCSP structure with no cavity because the cavity 5 in the WCSP structure 1 shown in FIG. 1 is filled with the resin 4.
In the following description, the WCSP structure with no cavity is referred to as a cavityless WCSP structure in some cases.
By employing the cavityless CSP structure with no cavity, a thermal stress generated in the cavity of the WCSP structure having a cavity can be significantly reduced, which can suppress an occurrence of warp.
Further, the cavityless CSP structure can suppress a reflection caused on an interface of the cavity (refractive index: 1) optically with the resin having the refractive index of approximately 1.5, with the result that it is possible to attain an increase of a light receiving quantity in the optical device 2.
Incidentally, in a lens-integrated camera module with a WCSP of a CCD or a CMOS image sensor, it is necessary to provide a function of an electromagnetic susceptibility (EMS) or an electromagnetic compatibility (EMC).
The EMS is a function for preventing a radiation electromagnetic field from another apparatus near the camera module and natural phenomena such as thunder and solar activity from inhibiting an operation of an electronic apparatus and for a protection from an external factor that causes a functional degradation of a system, a malfunction, and the like.
The EMC is a function for preventing the camera module itself from inhibiting an operation of another apparatus and preventing an electromagnetic interference (EMI) which may be an interference source at a certain level or more that affects a human body.
Image pickup apparatuses and camera modules which are equipped with the EMS or the EMC have been proposed (see, for example, Japanese Patent Application Laid-open Nos. 2010-283597, 2009-158863, and 2010-11230 (hereinafter, referred to as Patent Document 1, Patent Document 2, and Patent Document 3, respectively)).
The image pickup apparatus disclosed in Patent Document 1 includes a pixel area and has an image pickup element chip, in which a well is formed on a periphery thereof, and a metal shield which is disposed on the image pickup element chip and electrically connected with the well of the image pickup element chip.
In the camera module disclosed in Patent Document 2, around an optical device and shield glass, a light and electromagnetic shield is disposed.
The camera module disclosed in Patent Document 3 has a metal evaporation film that covers an entire side surface of the camera module.